1. Field of the Invention
The present invention relates to a nut which is less prone to loosening even if vibrations are applied.
2. Description of the Related Art
Conventionally, nuts threadedly engaging with bolts have been used in large quantities together with bolts in all types of structures including motor vehicles, machines, and electrical equipment. The nut achieves excellent operation and effects as a fastener because it is firmly fitted by strong tightening, but it has a drawback in that when being used at a place where vibrations are applied, it is loosened by the vibrations.
To overcome this drawback, a method has been used in which two nuts are used in lapped manner as what is called a double nut. The double nut achieves an effect of being less prone to loosening as compared with the case where one nut is used as before (single nut) even if it is used at a place where vibrations are applied.
However, since the double nut uses two nuts, it is higher in cost than the single nut, and requires time and labor two times those for the single nut in installation.